Kubuntu v8 (Linux v5.1) Update Sources?

I just reinstalled the Digi Linux v5.1 which is based on Kubuntu v8.
When I was using this same CDROM 12 months ago the Linux sources for the Adept updates were fine. Now the Kubuntu group has apparently changed these URL’s as only a few links are still valid.

Does anyone know where these new URL’s might be listed?

I suppose I could try to update Kubuntu to v9 or v10, however I don’t want to foul up or break the Digi tools. Last year when I updated to Kubuntu v9 I had trouble with the video drivers and the desktop became really messed up. So as an alternative, has anybody successfully upgraded Kubuntu to v9 or v10?